In batch orientated manufacturing processes so called "nutsch" filters or "box" filters or "tile" filters are still widely used. These filters all comprise a circular or more commonly a square or rectangular box having a drainage floor which may or may not be fitted with a filter cloth and side walls to retain the suspension to be filtered. The drainage floor is connected to a suction device such as a vacuum pump or centrifugal pump. After filtration and/or cake washing the filters are manually dug out.
Apart from the high labour requirement and frequent damage to any filter cloth, a great disadvantage of these filters is that the filter cake tends to suffer badly from cracking, resulting from cake shrinkage upon drying.
Alternative mechanically operated machines exist, but are of such a complexity and cost that in many cases the advantages of labour saving is not compensation enough for the capital investment.